I'd say buy cheap, most should come with 5 years guarantee, thank you consumer credit act, when it breaks bin it and get another.
We went medium-cheap with a Beko washer-dryer (I know, but space is limited) when we bought our first place a couple of years ago - about a week before the first year's warranty expired the drying stopped working.
Logged a call with the engineer, who was duly despatched to repair it free of charge...long story short, he said if you're not spending silly money you may as well look towards the lower end as there's very little difference once you get into the middle ranges from any manufacturer.
Also went through extended warranties as we'd had a reminder through about extending it through KnowHow - he said paying the c.£130 was incredible value as it basically meant we wouldn't have to worry about anything breaking in that time as it would just be replaced.
The bit that stuck in my mind though was one nugget; '...and of course, if it needs a complete replacement they'll take the old one away when they bring the new one in'!